1. Industrial field of application
The present invention relates to an automatic diaphragm control device for TV camera objective.
2. Prior art
As an automatic diaphragm control device for TV camera objective, a so-called one-way spring driven type has already been well known but has rarely been adopted in practice in view of its inconveniently limited range of useful driving voltage and poor reliability. A control device adapted for controllably driving the diaphragm in both directions, i.e., so as to open and close the diaphragm, respectively, has also been known and has been commonly employed, because the latter type provides a higher reliability and permits the consumed current to be effectively reduced.
However, demand for a more compact TV camera has recently increased and it has been found that the conventional control device of the bidirectional driving type cannot satisfactorily serve the objective of such a compact TV camra, since the conventional control device is too complicated in its structure to be correspondingly made compact.
3. Problems to be solved by the invention
A principal object of the present invention is, in view of the above-mentioned inconveniences, to provide an improved diaphragm control device of high reliability for a TV camera objective which includes a drive mechanism simplified and made compact by adopting the conventional one-way spring driven type while overcoming its inherent drawbacks, permitting both drive and control of the diaphragm to be achieved with a single power source, and leads to a reduction in current consumption.